/*
 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
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 *
 */

package java.rmi.activation;

import java.rmi.server.UID;

/**
 * The identifier for a registered activation group serves several
 * purposes: <ul>
 * <li>identifies the group uniquely within the activation system, and
 * <li>contains a reference to the group's activation system so that the
 * group can contact its activation system when necessary.</ul><p>
 *
 * The <code>ActivationGroupID</code> is returned from the call to
 * <code>ActivationSystem.registerGroup</code> and is used to identify
 * the group within the activation system. This group id is passed
 * as one of the arguments to the activation group's special constructor
 * when an activation group is created/recreated.
 *
 * @author Ann Wollrath
 * @see ActivationGroup
 * @see ActivationGroupDesc
 * @since 1.2
 */
public class ActivationGroupID implements java.io.Serializable {

  /**
   * @serial The group's activation system.
   */
  private ActivationSystem system;

  /**
   * @serial The group's unique id.
   */
  private UID uid = new UID();

  /**
   * indicate compatibility with the Java 2 SDK v1.2 version of class
   */
  private static final long serialVersionUID = -1648432278909740833L;

  /**
   * Constructs a unique group id.
   *
   * @param system the group's activation system
   * @throws UnsupportedOperationException if and only if activation is not supported by this
   * implementation
   * @since 1.2
   */
  public ActivationGroupID(ActivationSystem system) {
    this.system = system;
  }

  /**
   * Returns the group's activation system.
   *
   * @return the group's activation system
   * @since 1.2
   */
  public ActivationSystem getSystem() {
    return system;
  }

  /**
   * Returns a hashcode for the group's identifier.  Two group
   * identifiers that refer to the same remote group will have the
   * same hash code.
   *
   * @see java.util.Hashtable
   * @since 1.2
   */
  public int hashCode() {
    return uid.hashCode();
  }

  /**
   * Compares two group identifiers for content equality.
   * Returns true if both of the following conditions are true:
   * 1) the unique identifiers are equivalent (by content), and
   * 2) the activation system specified in each
   * refers to the same remote object.
   *
   * @param obj the Object to compare with
   * @return true if these Objects are equal; false otherwise.
   * @see java.util.Hashtable
   * @since 1.2
   */
  public boolean equals(Object obj) {
    if (this == obj) {
      return true;
    } else if (obj instanceof ActivationGroupID) {
      ActivationGroupID id = (ActivationGroupID) obj;
      return (uid.equals(id.uid) && system.equals(id.system));
    } else {
      return false;
    }
  }
}
